This invention relates generally to power operators for multi-passenger mass transit vehicles, more particularly to an emergency release mechanism for an electrically driven rotary door operator for opening and closing dual leaf swing doors such as used in multiple passenger vehicles including airport utility transports, school, and small transit buses.
Prior to the use of power operated door openers, doors of mass transit vehicles were manually opened and closed, typically by the vehicle operator. The strain of actuating these door openings and closings often led to long term medical difficulties for the vehicle operators. The need for power operated door openers led to the development of largely pneumatically actuated operators since in most large vehicles, use of air brake systems provides a reliable and convenient source of operating air at controlled pressures. U.S. Pat. Nos. 4,490,941 and 4,134,231 show examples of pneumatic powered door operators. However, these types of vehicles typically incorporate hydraulic brake systems. Therefore, no air supply is available, and hydraulic door drives are high in cost and involve excessive maintenance in order to prevent leaks and loss of brake system integrity. A growing need for a reliable low cost electric bus door operator now exists.
A power door operator for multi-passenger mass transit vehicles in disclosed in U.S. Pat. No. 5,332,279, the specification of which is hereby incorporated by reference. This type of prior art system incorporates an electrically driven gear motor operating drive arms rotating approximately 160xc2x0 in order to open and close a dual panel swing door set. A gear motor drive shaft operating through a sleeve clutch operates individually adjustable length drive arms of a drive bar in order to effect approximately 90xc2x0 rotation of each door from open to closed and closed to open. The operating door shafts located at the outer edges of each panel have door arms affixed thereto for connection to the above-mentioned reciprocating drive arms through door drive rods. Each door drive rod end is interfaced between its respective drive arm and door arm with a spherical rod end.
In order to obtain door operation independent of the door power drive, or door operation in the event of operator failure or in an emergency situation, the clutch fork actuating bar 20 is manually actuated by an actuator assembly, see FIGS. 4-5 of U.S. Pat. No. 5,332,279 which are labeled as prior art FIGS. 1 and 2 of the present application. As shown in FIG. 2, the normal position of the mushroom headed plunger 34 is extended somewhat from the surface of the movable panel 31 internally into the vehicle. In the event that uncoupling of the operator and door panels is desired, it is only necessary to move the plunger end 35 toward the panel, thereby actuating the clutch fork actuating bar 20, by compressing engaging spring 23 which allows the clutch fork assembly 16 to pivot on pins 17, thereby moving the slide collar and drive bar assembly 8 inward along shaft 10 and disengaging the gear box drive shaft teeth 12 and aperture slots 14. During clutch disengagement, drive rod ends 41 deflect inwardly, resulting in angular movement 43 of rods 40.
With the clutch disengaged, resilient edges and vehicle body door seal mounted on the vehicle structure, having been compressed on closing, provide an initial door opening force. Therefore, on disengagement of clutch teeth 12 and slots 14, the door panels are moved ajar. The doors can then be manually moved to an open position. When normal door operation is desired, it is only necessary to actuate the door motor. Re-engagement of the clutch teeth and apertures will again place the doors in their original relative positions for power operation.
A disadvantage of some types of prior art emergency releases which use toggle mechanisms as clamping devices require a large amount of travel of the clamping lever to achieve a very short stroke at the full load. A need exists for an emergency release mechanism which produces high final force within the mechanism resulting in relatively long travel of the lever under full load and a short travel of its driving arm.
The aforementioned related patent application, U.S. Ser. No. 10/136,164 is directed to an electric door operator for a mass transit vehicle. In the event of operator failure or in an emergency situation, there is a need for an emergency release mechanism which is compatible with this type of electric door operator.
The present invention is directed to an emergency release mechanism for use with a door operator of a multi-passenger mass transit vehicle for manually opening a door of this mass transit vehicle. The emergency release mechanism comprises a toggle mechanism having a first and second fixed pivot and a movable pivot positioned between this first and second fixed pivot. The first fixed pivot is secured to a wall portion of the vehicle. A target member is provided which is associated with and/or is a component of the door operator. This target member is capable of moving in a vertical direction to enable an emergency release of the door. A clamping lever is provided which has a first end and a second end. The first end of the clamping lever is pivotally attached to the second fixed pivot of the toggle mechanism and the second end of the clamping lever is capable of engaging the target member. A means is provided for mounting the clamping lever such that the clamping lever is capable of pivoting in a first and second direction to one of an engaging and disengaging position with respect to the target member. An actuating means is connected to the movable pivot of the toggle mechanism for pivoting the clamping lever in one of an engaging position and disengaging position with the target member for moving the target member in a vertical direction for achieving an emergency release of the door of the mass transit vehicle.
It is a primary object of the invention to provide an emergency release mechanism for use with a door operator of a multi-passenger mass transit vehicle.
It is a further object of the invention to provide an emergency release mechanism which is compatible for use with an electric rotary door operator.
It is another object of the invention to provide an emergency release mechanism which is compatible for use with safety release mechanisms.
It is yet another object of the invention to provide an emergency release mechanism which produces high final force within the mechanism resulting in relatively long travel of the lever under full load and a short travel of its driving arm.
It is still another object of the invention to provide an emergency release mechanism having a driving arm which is capable of traveling beyond a dead position while remaining in a released position.
In addition to the objects and advantages listed above, various other objects and advantages of the latch door operator disclosed herein will become more readily apparent to persons skilled in the relevant art from a reading of the detailed description section of this document.